Apparatus for the control of highway crossing signals



April 2, 1940.

R; A,., M cANN Filed Dec. 31, 1937 APPARATUS FOR THE CONTROL OF HIGHWAY CROSSING SIGNALS INV NTOR RonalWCazm. 1 BY f MS ATTORNEY my invention.

Patented Apr. 2, 1940 UNITED STATES PATENT OFFEQE APPARATUS OR run CONTROL or HIGH- WAY olwssmo SIGNALS Ronald A. McCann, Swissvale', Pa., assignor to The Union Switch & Signal Company, Swissvale, Pa., a corporation of Pennsylvania A Application December 31, 1937, Serial No. 18%824 WIT 6 Claims. (01. 246-430) highway for operating the highway crossin signals.

One feature of my invention is the provision of apparatus governing highway crossing signals without the necessity for insulated, track sections or track circuits. Other features of my invention will appear as my specification advances.

I shall describe one form of my invention, and then point out the novel features thereof in claims. 15

The accompanying drawing is a diagrammatic View of a preferred form Referring to the drawing, reference characters land la refer to the rails of a single track railway over which traffic moves in'both directions, and which intersectedat grade by a highway, designated as H. Located adjacent the intersection is a highway crossing signal, designated as S, which may be of any well-known type, and which is represented .onthe drawing as an audible highway crossing signal inthe' form of aelectric bell. It will beunderstoo'd, of course, that my invention is not restricted to this one form of highway crossing signal.

Located ata selected point to one side of the intersection is a track instrument, designated as Cl, which is suitably associated with the stretch of railway. This track instrument and such other track instruments as are mentioned in the specification (all track instruments used be- ,,,.period during which signal S operates.

ing preferably of the same type) may be of the well-known types of track instruments provided with a normally closed contact which is operated to-an open position in response to apassing train. For example, the track instrument may be of the microphone type covered by United States Letters Patent No, 1,834,077, issued to A. J. Sorensen, on December 1, 1931, or'th'e mercury contact type covered by United States Letters Patent No. 2',-

076,928, issued to H. G; Witmer on April 13, 1937.

The location of track instrument Cl is determined by the distance that trains using the railway travel during the operating period of .signal S. As track instrument C1 is preferably located at the. maximum distance traversed by trains during the warning period, the: location of:

track instrument Clisdependent upon the maxi- I mum, train. speed. and the minimum warning.

of apparatus embodying miles per hour, or 132 feet per second, and a minimum warning period of, say, 20 seconds, during which period a train will travel 2640' (1-32 x20) feet, track instrument Cl should be located 2640 feet from the intersection H. It is to be understood that my invention is not restricted to the figures selected above, but that any combination of maximum speed and minimum warning period desired-is included in the scope of my invention, as well as the selection of any arbitrary point for the location of the track instrument Cl.

Located between the highway intersection and track instrument Cl is a second track instrument C2 The location of track'- instrument C2 in relation to-track instrument Cl Will be discussed later, as it can best be understood in connection with the operation of my apparatus.- I A normally energized relayRl is controlledby trackinstrument- Clthrough a simple circuit including track instrument Cl, winding of relay El, and a battery 22. Similarly, a'norinially energizedrelay R2 is controlled by track instrument C2 through a simple circuit includingtrack instrument C2, Winding of relay R2 and battery 22.

A normally energized slowreleas'in'g directional stick relay R6 is controlled jointly by relays RI and R2. The stick circuit for relay R6 passes from terminal B ofa. source of current, such as a battery not shown, through front contact 2 of relay Rl, front contact 3 of relay R2, front contact 4' of relay R8, and'vvindin'g of relay'Rt, to the other. terminal C of the source of current. The

' pick-up circuit forrelay RB passes from" terminal 13'; through front contact 2 of relay RI, front contact 3 of relay R2, contact 5 of a time element device TEll, andW-inding of relay ES, to terminal C. i'ime element device TEI (and a similar device 'IEZ referred to hereinafter) may be of any of the usual types oftime element devices, especially that type disclosed in the United States application for Letters Patent, Serial No. 119,437, filed January 7, 1937-, by E. Ashworth, for Thermal relays. Time element device TEl has a heating element l9 which closes the normally open contact 5 at the expiration of a fixed period, such for example'as 10 seconds, after the heating element i9 is energized. The circuit for heating element I 9 passes from terminal B, through front contact 2 of relay'Rl, front contact 3 of relay R2, back contact M of relay R6, and heating element I9 to terminal C.

A. track instrument C3 is located adjacent the intersection H and suitably associated with the stretch of railway tracksoas to be free from actuation by vehicles using the highway. A normally energized relay R3 is controlled by track instrument C3 through a simple circuit including track instrument C3, winding of relay R3, and a battery 23. Track instruments C4 and C5 are located on the opposite side of the intersection from track instruments CI and C2, track instrument C4 controlling normally energized relay R4, track instrument C5 controlling normally energized relay R5, and relays R4 and R5 jointly controlling the normally energized slow releasing directional relay R8 and time element device IE2, by circuits similar to those traced for the control of relays RI, R2 and R6 and time element device TEI by track instruments CI and C2. The locations of track instruments C4- and C5 are determined in a manner similar to the determination of the location of track instruments CI and C2.

The apparatus further includes a normally energized stick relay R1. The stick circuit for relay R1 passes from one terminal of a battery 25 through line wire 26, front contact 6 of relay RI, line wire 21, front contact 1 of relay R1, winding of relay R1, line Wire 28, front contact 9 of relay R5, and line wire 29 to the other terminal of battery 25. Back contact II) of relay R6 provides a shunt path around front contact 6 of relay RI, and back contact II of relay R8 provides a shunt path around front contact 9 of relay R5 in this stick circuit for relay R1, The pick-up circuit for relay R1 is normally open, and passes from one terminal of battery 25, through line wire 28, front contact 6 of relay RI, line wire 21, back contact I2 of relay R5, winding of relay R1, line wire 28, front contact 9 of relay R5, and line wire 29, to the other terminal of battery 25. The immediate operating circuit for signal S passes from one terminal of battery 25, throu h line wire 38, winding of signal S, line wire 3|, and back contact I3 of relay R1, to the other terminal of battery 25.

When no train is Within the control stretch, the apparatus is in its normal condition. In this condition, the relays controlled by the associated track instruments are energized, the slow releasing relays RB and R8 are energized over their respective stick circuits, and relay R1 is energized over its stick circuit. Also, the operating circuit for signal S is open and signal S does not operate.

The governing of the highway crossing signal S by the control apparatus may be understood from a description of the operation of the apparatus in response to an east-bound train approaching the highway.

The actuation of track instrument CI by the passing train deenergizes relay RI, which opens front contact 6 and deenergizes relay R1. Relay R1 opens front contact 1, and closes back contact I3 which completes the circuit for signal S and signal S is placed in operation.

Relay RI also opens front contact 2 and relay RB deenergizes, opening front contact 4 and closing back contacts I0 and I4 at the end of its slow release period. This slow action permits front contact 1 of relay R1 to open before front contact 6 of relay RI is shunted by back contact IU of relay R6.

The actuation of track instrument C2 by the passing train deenergizes relay R2 which opens front contact 3.

When the train completely passes track instrument Cl, relay RI reenergizes and picks up to close its front contacts 2 and 6. Signal S still operates because the stick circuit for relay R1 is open at front contact 1 of relay R1, and the pick-up circuit for relay R1 is open at back contact I2 of relay R3. When the train completely passes track instrument C2, relay R2 reenergizes and closes front contact 3 which completes the heating circuit for time element relay TEI. The heating of element I9 for a time period (10 seconds, for example) closes contact 5 and, relay R6 reenergizes, When this happens, back contact IB opens to remove the shunt across front contact 6 of relay RI in the stick circuit of relay R1, and back contact I4 opens to open the heating circuit for time element relay TEI. Front contact 4 of relay R6 also closes to complete the stick circuit for relay R6, which holds the relay energized after contact 5 of time element device TEI opens to break the pick-up circuit for relay R6 upon cooling of element I9 of time element device TEI.

When the train reaches track instrument C3, relay R3 deenergizes and closes back contact I2 which completes the pick-up circuit for relay R1 as previously traced. Relay R1 picks up and. opens back contact l3 which stops the operation of signal S. Moreover, the closing of front contact 1 of relay R1 completes the stick circuit for relay R1, which holds the relay energized after back contact I2 has been opened by the reenergizing of relay R3. Relay R3 reenergizes after the train completely passes track instrument C3.

The train in receding from the highway intersection actuates track instrument G4, which in turn deenergizes relay R4. The release of relay R4 opens front contact I5 to break the stick circuit for relay R8. At the end of its slow release period, relay RS becomes deenergized, thereby opening front contact I6 and closing back contacts II and I1. The train in passing track instrument C5 actuates the instrument, and deenergizes relay R5 to open front contacts I8 and 9. The stick circuit for relay R1 is not opened at front contact 9 of relay R5 because back contact II of relay R8 provides a shunt path around front contact 9 of relay R5. From this, it can be seen that the distance between track instruments C4 and C5 may have any convenient value which permits the actuation of track instrument C4, the deenergization of relays R4 and R8, and the closing of back contact II of relay R8 prior to the actuation by a train moving at maximum speed of track instrument C5, and the consequent deenergization of relay R5 and the opening of front contact 9. For example, assuming a maximum speed of miles per hour, or 132 feet per second, and a release period for the slow release relays of the order of three-quarters of a second, during which period a train will travel 99 feet, then the distance between track instruments C4 and C5 should be at least 100 feet. It follows that, with the apparatus proportioned in the manner just described, the relay R8 functions as a directional relay for preventing the track instruments C4 and C5 from governing the controlling means for signal S when actuated by a train receding from the intersection.

When the train completely passes track instrument C4, relay R4 reenergizes to close front contact I5. When the train completely passes track instrument C5, relay R5 reenergizes to close front contact 9, which reestablishes the normal stick circuit for relay R1. Front contact I8 of relay 7 R5 also closes, which "completesa heating circuit instrument forriniti'atinguthe operation ofthe for time element relayTEZ, similar to that traced above for relay 'TEI. Element 20 heats, and, at the expiration of a time period,- contact 2| of time element relay TE2 closes, completing the pick-up circuit for relay R8. Relay RB energizes, back contact. 1 I opens to remove the shunt across front contact 90f relay R5, and front contact it closes to complete the stick circuit for relay RB. This stick circuit holds relay R8 energized when contact 2! opens after heating element 20 of time element relay TE2 cools.

Thus,it can be seen that the apparatus operates the signal when a train approaches the intersection, and automatically terminates the operation of the signal when the train reaches the intersection.

The apparatus operates in asimilar manner for a-train approaching the highway in theopposite direction, which may be readily understood by reference to the drawing, without tracing the operation in detail,

The apparatus as-here disclosed is simple and reliable, and requires no track circuits. As a result, a reliable highway crossing signal control may be effected without the necessity for break;

ing into a rail section orinsulating a portion of Although I have described and illustrated only one form of apparatus embodying my invention,

it is to be understood that various changes and modifications may be made therein within the scope of the appended claims without departing from the spirit and scope of my invention. I

Having thus described my invention, what I claim is:

1. In combination, a stretch of railway track intersected by a highway, a highway crossing signal located adjacent the intersection, a first track instrument associated with the stretch at a selected point to one side of the intersection, a first normally energized relay controlled by said first track instrument, opera-ting means governed by a front contact of said first normally energized relay and effective when a train operating in a first direction over said stretch actuates said first instrument to deenergize said first normally energized relay for operating the high way crossing signal, a second track instrument associated with the stretch at a selected point on the same side and nearer the intersection than the first track instrument, a second normally energized relay controlled by said second track instrument, a slow releasing relay normally energized over front contacts of said first and said second normally energized relays, and means in cluding a back contact of said slow releasing relay to prevent said front contact of saidfirst track instrument from governing said operating means.

2. In combination, a stretch of railway track intersected by a highway, a highway crossing signal located adjacent the intersection, a first track instrument associated with the stretch at said first track instrument, controlling meansincluding a front contact of said first nor mally energized relay and effective when a train operating over said stretch in a direction [to approach the intersection actuates said first.

highway crossing signah'a second trackinstr ment associated with the stretch at a-'select'ed point between the first track con-tactor instrument and the intersection,--a second normally energized relay controlled by said second track instrument, a normally energized slow releasing stick relay, a'stickkcircuitfior-said'stick rel'ay including front contacts of said first and said a contact of said time element 'devic'efandmea-ns including a back contact of said stick relay and effective when a train operating over said stretch in the opposite direction actuates said second instrument to prevent said controlling means from initiating the operation of said signal.

3; In combination, a stretch of railway track intersected by a highway, a highway crossing signal located adjacent the intersection, a first track instrument'associated with the stretch at a selected point "to one side of the intersection, a first normally energized relay controlled by said first track instrument, a normally energized stick relay, a stick circuit for said normally energized stick relay including a front contact of said first normally energized relay, operating means in cluding a back contact of said normally ener-' gized stick relay for operating the highway crossing signal, a second track instrument associated with the stretch at a selected point on the same side and nearer the intersection than said first track instrument, a second normally energized relay controlled by said second track instrument, a normally energized slow releasing stick relay, a stick circuit for said slow releasing stick relay including front contacts of said first and saidsecond normally energized relays in series, a time element device controlled by front contacts of said first and said second normally energized relays and a back contact of said slow releasing stick relay, a pick-up circuit for said slow releasing stick relay including front contacts of said first and said second normally energized relays and a contact controlled by said time element device, and means including a back contact of said slow releasing stick relay to prevent said operating means from operating said signal when a train recedes from the intersection.

4. In combination, a stretch of railway track intersected by a highway, a highway crossing signal located adjacent the intersection, a first track instrument associated with the stretch at y p, 5 second normally energized relays in series and a selected point toone side of the intersection,

a first normally energized relay controlled by said first track instrument, a normally energized stick relay, a stick circuit for said normally energized stick relay including a front contact of said first normally energized relay, operating means including a back contact of said stick relay for operating the highway crossing signal, a second track instrument associated with the stretch at a selected point on the same side and nearer the intersection than said first track instrument, a second normally energized relay controlled by said second track instrument, a normally energized slow releasing relay controlled by front contacts of. said first and said second normally energized relay in series, directional means including a back contact of said slow releasing relay to prevent said operating means from operating said signal when a train recedes from the intersection, a third track instrument located adjacent the intersection, a third normally energized relay controlled by said third track instrument, and means governed bya back contact of said third normally energized relay for stopping the operation of the highway crossing signal.

5. In combination, a stretch of railway track intersected by a highway, a highway crossing signal located at the intersection, a first track instrument associated with the stretch at a selected point to one side of the intersection, a first relay governed by said first instrument, operating means for operating said signal governed by said first relay and operative when a train approachingthe intersection actuates said first instru ment, a second track instrument associated with the stretch intermediate said first relay and the intersection, a second relay governed by said second instrument, a directional relay governed by said first and said second relays, and means governed by said directional relay operative when a train receding from the intersection actuates said second instrument for rendering said first relay ineffective to govern said operating means. 6. In combination with a stretch of railway track intersected by a highway and provided with a highway crossing signal located adjacent the intersection, a first track instrument associated with the stretch to one side of the intersection, operating means governed by said first instrument and effective when a train operating in a first direction over said stretch actuates said first instrument for initiating the operation of said signal, a second track instrument associated with the stretch intermediate said first instrument and the intersection, a slow acting relay controlled jointly by said first and second track instruments, and means governed by said slow acting relay and effective when a train actuates said second instrument prior to actuating said first instrument for preventing said first instrument from governing said operating means.

RONALD A. MCCANN. 

